Fiber-optic reflectometry techniques are used for detecting and analyzing impairments and events that affect the optical properties of an optical fiber. Various fiber-optic reflectometry techniques are known in the art. Such techniques are described, for example, by Takada et al., in “New measurement system for fault location in optical waveguide devices based on an interferometric technique,” Applied Optics, volume 26, issue 9, 1987, pages 1603-1606; by Barnoski and Jensen, in “Fiber waveguides: a novel technique for investigating attenuation characteristics,” Applied Optics, volume 15, issue 9, 1976, pages 2112-2115; and by Bar-Am et al., in “OFDR with double interrogation for dynamic quasi-distributed sensing,” Optics Express, volume 22, issue 3, 2014, pages 2299-2308, which are incorporated herein by reference.
Additional examples of fiber-optic reflectometry schemes are described by Arbel and Eyal, in “Dynamic optical frequency domain reflectometry,” Optics Express, volume 22, issue 8, 2014, pages 8823-8830; and by Zhang and Bao, in “Distributed optical fiber vibration sensor based on spectrum analysis of Polarization-OTDR system,” Optics Express, volume 16, issue 14, 2008, pages 10240-10247, which are also incorporated herein by reference.
Some fiber-optic reflectometry techniques are based on Optical Time-Domain Reflectometry (OTDR). OTDR-based schemes are described, for example, by Juarez et al., in “Distributed fiber-optic intrusion sensor system,” Journal of Lightwave Technology, volume 23, issue 6, 2005, pages 2081-2087; and by Yuelan et al., in “Distributed vibration sensor based on coherent detection of phase-OTDR,” Journal of Lightwave Technology, volume 28, issue 22, 2010, pages 3243-3249, which are incorporated herein by reference.
Other fiber-optic reflectometry techniques are based on Optical Frequency-Domain Reflectometry (OFDR). OFDR-based schemes are described, for example, in the articles by Bar-Am et al. and by Arbel and Eyal, cited above, as well as by Ito et al., in “Long-range coherent OFDR with light source phase noise compensation,” Journal of Lightwave Technology, volume 30, issue 8, 2012, pages 1015-1024, which is incorporated herein by reference.